Abstract The central nervous system (CNS) acquires its vasculature by angiogenesis, a process that is critical for its development and repair. Our work has changed notions of cerebral vascularization which implied that blood vessels sprout passively into the brain parenchyma from pial vascular plexuses to meet metabolic needs of growing neuronal populations or treated endothelial cells of the CNS as a homogenous population. Based on origins, anatomical location, independent growth patterns and developmental regulation, forebrain vascular networks fall into two categories: pial and periventricular. The periventricular vascular network that develops in advance of and independent of neuronal development is strategically positioned to provide support and critical guidance cues to instruct neurogenesis and GABAergic interneuron migration in the developing telencephalon. These findings offer new solutions for transplanted primary neuronal precursors that are unable to migrate and integrate into regions requiring new neurons in the absence of proper guidance mechanisms. This application will explore this novel paradigm of neurovascular interactions in diverse ways. It will identify novel angiogenesis mechanisms underlying the origin and etiology of neuropsychiatric diseases. It aims to highlight the novel concept that endothelial GABA signaling is indispensable for brain development shaping postnatal and adult behavior. It attempts to rescue abnormal vascular GABA signaling during embryonic development as a therapeutic approach for long-lasting mental health outcomes. It will examine whether periventricular?like human endothelial cells promote human GABAergic neuronal migration to facilitate development of novel cell based therapies for GABA-related diseases. Results will have far-reaching effects on concepts and mechanisms of regulation of angiogenesis, offer new perspectives on telencephalic histogenesis principles and will lead to discoveries with unprecedented implications for regenerative medicine and treatment of many neurological and psychiatric diseases.